Health & Fitness
Body Fat Calculator
Estimate adult body fat percentage from circumference measurements using the U.S. Navy method. Review estimated fat and lean mass, screening ranges, measurement guidance, and a professional PDF report.
Estimated body fat0%
Estimated fat mass0 kg
Estimated lean mass0 kg
General screening category-
Screening reference
Estimated body-fat range
| Sex | Essential | Athletic | Fitness | Average | Higher range |
|---|---|---|---|---|---|
| Male | 2-5% | 6-13% | 14-17% | 18-24% | 25%+ |
| Female | 10-13% | 14-20% | 21-24% | 25-31% | 32%+ |
Decision view
Modeled body-composition split
0%estimated body fat
General screening category -
How to use Body Fat Calculator
- Select the equation sex and enter height, weight, neck, waist, and hip circumference where required.
- Measure each circumference at the documented anatomical site with the tape level and without compressing the skin.
- Read body-fat percentage together with estimated fat mass and lean mass; use repeated measurements to examine direction.
- Keep measurement method and conditions consistent, and do not substitute the result for clinical assessment.
Calculator guide
Understanding Body Fat Calculator
Circumference methods estimate body fat from tape measurements and statistical equations. Consistent technique matters because small measurement changes can alter the result.
Calculation method
How the calculation works
The U.S. Navy circumference method estimates body fat from height, waist, neck, and for women, hip circumference. Apply the sex-specific U.S. Navy circumference equation using base-10 logarithms, then multiply the estimated percentage by body weight for fat and lean mass.
Measurement protocol
Tape technique matters more than extra decimals
Circumference equations are sensitive to small changes in the entered measurements. Repeatable technique improves trend usefulness.
Composition view
Interpreting fat mass and lean mass
The estimated percentage partitions entered body weight into two modeled components.
Worked situations
Practical examples
- Estimate body fat from consistent neck, waist, height, and optional hip measurements.
- Track changes using the same tape-measure technique over time.
- Compare the estimate with BMI while recognizing that the measures answer different questions.
Better inputs
Useful tips
- Measure with a level tape under consistent conditions.
- Use the same anatomical landmarks each time.
- Track trends rather than over-interpreting one estimate.
Before relying on the result
Limitations and common mistakes
- The method is an estimate and can differ from clinical measurements.
- Category interpretation depends on sex, age, and reference standard.
- It is not intended for diagnosis, pregnancy, or pediatric assessment.
Reference
Key terms
- Circumference
- A tape measurement around a specified body location.
- Fat mass
- Estimated weight attributed to body fat.
- Lean mass
- Estimated non-fat body mass.
- Navy method
- A circumference-based body-fat estimation equation.
Important note
Calculated from the entered measurements using the displayed method. It is a general reference and does not replace diagnosis or individualized professional guidance.
Frequently asked questions
Which body-fat method is used?
The calculator uses sex-specific U.S. Navy circumference equations.
Why do measurements need to be consistent?
Small differences in tape placement or tension can materially affect the estimate.
Is this more accurate than BMI?
They measure different things; neither is a direct clinical body-composition scan.
Can it diagnose obesity or health risk?
No. It is a screening estimate and requires professional context.